From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E952C433DB for ; Thu, 11 Feb 2021 15:57:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D562464DE2 for ; Thu, 11 Feb 2021 15:57:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230182AbhBKP5H (ORCPT ); Thu, 11 Feb 2021 10:57:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:52478 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230268AbhBKPT5 (ORCPT ); Thu, 11 Feb 2021 10:19:57 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 569AC64F22; Thu, 11 Feb 2021 15:06:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613055996; bh=xAiGLbiCn1pYgkjXtviHEXZeYJA+xkTi4eQyjog8xFE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B2y3tsAgRFAgjlpq9n80HQw/tjoNN3DWESBw6ZDd94XIOpNDjk0WGmobgoXss2uhQ wGKAHYGcmRl0ks+BEmmsg+nZ/1FbxyW7PNLea8w2dRBzQ44ji2jxInq8pVG2S5WURf 287M8e37q2BUbkRUeq6d4q3l/Fc8AdP492PSehbg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, zhengbin , Jens Axboe , Jack Wang Subject: [PATCH 4.19 02/24] block: fix NULL pointer dereference in register_disk Date: Thu, 11 Feb 2021 16:02:36 +0100 Message-Id: <20210211150147.866158359@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210211150147.743660073@linuxfoundation.org> References: <20210211150147.743660073@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: zhengbin commit 4d7c1d3fd7c7eda7dea351f071945e843a46c145 upstream. If __device_add_disk-->bdi_register_owner-->bdi_register--> bdi_register_va-->device_create_vargs fails, bdi->dev is still NULL, __device_add_disk-->register_disk will visit bdi->dev->kobj. This patch fixes that. Signed-off-by: zhengbin Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Jack Wang --- block/genhd.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/block/genhd.c +++ b/block/genhd.c @@ -652,10 +652,12 @@ exit: kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD); disk_part_iter_exit(&piter); - err = sysfs_create_link(&ddev->kobj, - &disk->queue->backing_dev_info->dev->kobj, - "bdi"); - WARN_ON(err); + if (disk->queue->backing_dev_info->dev) { + err = sysfs_create_link(&ddev->kobj, + &disk->queue->backing_dev_info->dev->kobj, + "bdi"); + WARN_ON(err); + } } /**